This invention relates, in general, to containers, including, but not limited to, containers capable of serving as moisture barriers, providing electro-static discharge protection, and having an internal environmental monitor.
Typically, semiconductor manufacturers store and ship plastic encapsulated electronic components within a sealed container. The sealed container provides, among other things, a low moisture environment and electro-static discharge (ESD) protection for the plastic encapsulated electronic components. Moisture present within the sealed container may be absorbed by the plastic encapsulating material. Subsequent high temperature operations such as surface mounting of the plastic encapsulated electronic components, may vaporize the absorbed moisture thereby generating a tremendous pressure within the plastic encapsulating material. The pressure may crack the plastic encapsulating material and result in failure of the encapsulated electronic component.
In addition to the plastic encapsulated electronic components, a desiccant and a humidity indicator are typically enclosed within the sealed container. The desiccant absorbs any moisture trapped within the sealed container during the sealing operation. The humidity indicator provides a visual display of the amount of moisture present within the sealed container. The sealed container must be opened in order to inspect the encapsulated humidity indicator. If the humidity indicator indicates that the sealed container had a humidity level within an acceptable level, the plastic encapsulated electronic components, a new desiccant, and a new humidity indicator are sealed inside another container. Thus, unsealing the container to inspect the humidity indicator adds considerable expense to the storage and shipping of plastic encapsulated electronic components. Accordingly, it would be advantageous to have a low cost means for monitoring the internal environment of a sealed container without unsealing the container.